Valve bag



y 15, 1956 w. w. HAHN EI'AL 2,745,594

VALVE BAG Filed March 22, 1955 Ire F i 5.2

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INVENT R. z/wg i BY 7L7 K M A TTORNE Y5 United States Patent VALVE BAG William W. Hahn, New Hope, and Ray H. Brodt, Nazareth, Pa., assignors to Universal Paper Bag Co., New Hope, Pa., a corporation of Pennsylvania Application March 22, 1955, Serial No. 496,036

2 Claims. (Cl. 229-625) This invention relates to multi-ply paper valve bags. Such bags are widely used in industry for the packaging and shipment of pulverulent, granular or other dry, flowable materials, as for example, fertilizer, cement, grain and the like. Valve bags are usually gusseted, and one of the upper gusseted corners is folded inwardly to form an open passageway through which a filling tube may be inserted to fill the bags. After the bag is filled, the tube is withdrawn, and the wall of the passageway is pressed against the bag wall by the contents of the bag to form a seal.

The seals formed in this manner have not been entirely satisfactory for they have not been tight seals, and under some circumstances serious losses of the bagged material occur. Such seals have been tolerated because of the very decided advantages of the valve for filling purposes, but many efiorts have been made over a long period of years to provide a valve construction which would provide an improved seal. Among the improved constructions which have found commercial acceptance are the valve extension type and the sleeve valve type. In these constructions the extension or sleeve which extends inwardly beyond the valve itself is usually formed by an additional piece of material which must be inserted in the valve itself. While such extensions and sleeves have improved the sealing qualities of the valve, they have added substantially to the cost of the bag.

It is an object of the present invention to provide a multi-ply valve bag having an improved valve construction which greatly improves the sealing qualities of the ordinary valve, and which may be made at a cost which is little or no greater than the cost of an ordinary valve.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawings, in which,

Figure 1 is a front elevation of a corner of a bag having a valve therein.

Figure 2 is a plan view with the walls spread open to show the valve construction.

Figure 3 is a side elevation of an empty bag.

Figure 4 is a side elevation of a filled bag.

Figure 5 is a section on the line 55 of Figure 2.

Referring to the drawings, the bag is a multi-ply bag consisting of a plurality of plies of paper 1, 2 and 3. The

bag is formed with a longitudinal gusset 4 and the valve 5 is formed in the usual manner by folding the top corner of the material inwardly at the gusset. The top of the bag is closed in any desired manner, as by a binding strip 6 secured by stitching 7.

The construction thus far described is old and common and results in the conventional type of valve 5. The novel features of the present invention are as follows. In the following description, we shall, for convenience, use the term valve apron to refer to that portion of the bag from which the valve is actually formed, i. e. the area 2,745,594 Patented May 15,1956

shown in Figure 2 which is bounded by the lines a, b, c, d, e and f. In the actual construction, all of these lines are fold lines except line d which is the free edge of the valve opening, and lines 0 and e which are the edges which are bound by the binding strip 6. The length of the lines 0 and e is the length of what is known as the valve notch.. The line a is the fold line along whichthe valve apron is joined to the gusset and the lines b and f are the fold lines along which the valve apron is joined to the front and back panels of the bag. A fold line 8 extends across the valve apron from the mid point of line a to the mid point of edge d, and the point of inter: section of the fold line 8 with edge d is known as the apex of the valve.

According to the present invention, the valve apron is crimped, preferably throughout its area, to form a series of corrugations 9 also extending across the valve apron parallel to the fold line 8. Second, the valve apron is provided with a plurality of lines of perforations 10 which extend from the fold line a to the valve edge d. Preferably these lines of perforations extend diagonally across the valve apron with two of the lines intersecting at the valve apex.

With these two features of corrugations and perforations embodied together in the valve apron, the improvement in the sealing qualities of the valve is very marked. In the first place, the presence of the perforations in the valve apron permits the rapid escape of air. This, together with the increased flexibility of the apron due to the combined effect of the corrugations and perforations, makes it possible for the valve to flip up toward closing position as the filling tube is withdrawn from the valve. The valve will not close completely until the bag assumes a horizontal position causing the material to exert pressure against the valve. Nevertheless, the fact that the valve assumes a position to be closed quickly is of great importance in view of the manner in which such bags are handled when they are being filled.

The bags are filled in vertical position and after the filling tube is removed, the filled bags drop to a conveyor, still in vertical position. When they are re moved from the conveyor they are stacked in horizontal position. With the ordinary valve, after the filling tube is withdrawn, the valve tends to remain wide open in the conformation of the filling tube, and it does not close until the bag is stacked in horizontal position and is subjected to pressure from the packed material.

With the present valve, however, there is a tendency for the valve to flip upwardly as the bag pulls away from the filling tube, and this tendency is increased by the jar and the sudden release of air which occurs when the bag is dropped onto the conveyor. By the time the bag is stacked, therefore, the valve is usually close to closing position and the first impact or pressure of material closes it tightly, thus minimizing the opportunity for loss of material.

In this connection, it is to be noted that the favorable results which have been observed from the use of the present invention accrue from the conjoint use of corrugations and perforations. Neither feature, used alone, gives any significant improvement over the ordinary valve.

It will be understood that the invention may be variously modified and embodied Within the scope of the subjoined claims.

We claim as our invention:

1. A valve bag comprising a multi-ply paper body having a longitudinal gusset and having a top corner folded in at the gusset to form a valve apron, said valve apron having a free edge forming the inner end of the valve opening and a parallel fold line along which it is joined to said gusset, said apron also having a center fold a .Y r 4 line extending from the mid point of said free edge to the of said lines of perforations intersect said center fold mid point of said parallel fold line and forming at said line at the apex of the valve.

free edge the apex of the valve, said apron also having a series of corrugations extending across said apron in References Cited mthe file of thls Pawnt directions perpendicular to said free edge and to said 5 UNITED STATES PATENTS parallel fold line, and said apron also havinga plurality of 1 444 118 Hartman Feb 6 1923 linesof perf orations extending diagonallv across said 1:745:312 Oman i 1930 apron and .dlagonally across said corruagtwns 1n d1re- 2,660,190 Doyle 24, 1953 32:5 which interscct'said free edge and said parallel fold m FOREIGN TS 2. A valve bag as claimed in claim 1 in which two ,9 France ..'Dcc. 31, 1947 

